In a landmark development, the US Government invalidated the last of three of Rambus' claims to key patents that saw it locked in successful patent-infringement lawsuits against the likes of NVIDIA and Hewlett-Packard, among others. The three patents are related to memory chip design, and are among the most valuable patents held by Rambus. An appeals board at the U.S. Patent and Trademark Office (USPTO) declared the patent invalid on January 24, according to a ruling posted on their website. The previous two were declared invalid in September, 2011.

The Barth patents have been used by Rambus to sue a long list of companies in the PC industry, including NVIDIA and AMD. It has been used to extract millions of dollars in licensing fees from the likes of the already cash-strapped AMD, through settlements. NVIDIA's patience seems to have paid off. Rambus can appeal the latest decision from the PTO. "We're evaluating our options," said company spokeswoman Linda Ashmore.Source: Reuters